81413220 has 48 divisors (see below), whose sum is σ = 260523648. Its totient is φ = 18608640.

The previous prime is 81413219. The next prime is 81413303. The reversal of 81413220 is 2231418.

It is a super-2 number, since 2×81413220² = 13256224781536800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96501 + ... + 97340.

It is an arithmetic number, because the mean of its divisors is an integer number (5427576).

Almost surely, 2^81413220 is an apocalyptic number.

It is an amenable number.

81413220 is an abundant number, since it is smaller than the sum of its proper divisors (179110428).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81413220 is a wasteful number, since it uses less digits than its factorization.

81413220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193860 (or 193858 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 81413220 is about 9022.9274628582. The cubic root of 81413220 is about 433.4093844167.

Adding to 81413220 its reverse (2231418), we get a palindrome (83644638).

The spelling of 81413220 in words is "eighty-one million, four hundred thirteen thousand, two hundred twenty".